1. Field of the Invention
The present invention relates generally to windshield washing systems for motor vehicles such as automobiles and, more particularly, to a system for heating the washer fluid to deice either the windshield or some other vehicle window.
2. Description of the Prior Art
Automobile owners are often plagued during the winter with the problem of having a layer of ice deposited on the windshields of their vehicles by the weather conditions occurring at that time of the year. Such ice deposits are troublesome because they block the driver's vision thereby creating a safety hazard and because they are very difficult to remove. The driver must usually get out of the automobile into the cold winter weather to repeatedly scrape the windshield to clear it of ice. In addition, if the windshield wipers are embedded in the ice accumulation, any attempt to operate the wipers before clearing the wiper blades from the ice may result either in an overheated wiper motor or broken wiper linkages.
In an attempt to solve the problem of an iced-over windshield, various devices have been developed in the past to distribute a heated fluid onto the windshield to remove the ice. The fluid to be heated is often that fluid contained in the reservoir of the conventional windshield washing systems used in most cars today. Many of the prior art deicers heat the washer fluid by some type of a heat exchange relationship with the cooling liquid contained in the radiator or heater hose which has been warmed by passing through the engine. Such devices are generally shown in U.S. Pat. Nos. 3,243,119 to Merkle, 3,292,866 to Benner and 3,632,042 to Goulish. Other of the prior art deicers utilize an electrical heating means for warming the washer fluid to be distributed onto the windshield. Such devices are shown in U.S. Pat. Nos. 3,319,891 to Campbell and 3,427,675 to Tibbet, and also in the German Patent No. 1,909,956.
Those prior art deicers which utilize the heated engine coolant to heat the washer fluid have the disadvantage that, when the engine is first started and is cold, the washer fluid will not be heated promptly. Such a system is not effective to remove any ice from the windshield or to prevent the formation of ice until the engine gets hot enough by running for awhile to adequately heat the washer fluid by contact with the engine coolant; this may take up to 10 or 15 minutes in extremely cold weather. If the driver has to wait this length of time for the washer fluid to be heated, there is no time savings compared to the time it would take him to manually scrape the windshield clear of ice, or any significant advantage over the conventional defrosters on an automobile which are also effective in clearing ice from the windshield at about the same time, i.e., when the engine coolant becomes thoroughly heated.
The prior art devices which utilize an electrical means for heating the washer fluid, while not dependent on the engine coolant being hot to perform their heating function, have the disadvantage that there is a continuous drain on the vehicle battery or whatever other source of electrical power is being used to heat the fluid. Such a drain decreases the life expectancy of the vehicle battery and may result in the battery not having sufficient energy to start the car if the deicing system is used for a long period of time. In addition, such a continual drain on the battery puts an additional burden onto the charging system for recharging the vehicle battery, thereby decreasing its life expectancy. Of course, if one shuts off the deicing system to conserve the battery and the charging system of the car, then the salutory effect of the deicing system is lost and the driver is reduced to the traditional method of scraping the windshield.